1. Field of the Invention
The present invention is generally related to a die assembly apparatus and, more particularly, to a die assembly apparatus that uses hydraulic actuators and is configured to reduce cost and improve the manufacturing process for making a wax propeller.
2. Description of the Prior Art
It is well known that certain objects can be manufactured by injecting a molten material into a die assembly that can typically comprise two or more die assembly segments that define a cavity therein. Skilled artisans in the field of molding and casting are very familiar with many different techniques related to injection molding and die casting procedures.
U.S. Pat. No. 4,043,385, which issued to Petrenchik on Aug. 23, 1977, discloses a molding apparatus. The apparatus is intended for use in molding components such as turbine blade assemblies and the like without the use of complex multipart molds. It comprises first and second mold halves carried by cooperating platens for relative movement toward and away from one another along a path. A connecting assembly is provided for attaching the first mold half to its respective platen in a manner which permits it to have free movement in directions perpendicular to the path and rotary movement about an axis parallel to the path. Additionally, a control assembly is provided to cause the first mold half to undergo predetermined transverse and rotary movement during movement along the path toward and away from the second mold half.
U.S. Pat. No. 4,414,171, which issued to Duffy et al on Nov. 8, 1983, describes a method for making an injection molded propeller. The method relates to the manufacture of an inexpensive injection molded propeller for mounting on a drive shaft. The drive shaft is attached to the hub of the propeller by a chemical and thermal shrink fit and by deformation due to the rotational forces of the propeller thereby producing a positive locking hub on the drive shaft. The propeller may be used, not only for remote piloted missiles and aircraft, but can also be used with different types of boat inboard and outboard drives, vehicles and equipment requiring a propeller having a positive locking system for securing the propeller or the like to the drive shaft.
U.S. Pat. No. 4,524,943, which issued to Busch et al on Jun. 25, 1985, describes an injection mold for the manufacture of sealing elements consisting of elastic material and having undercuts, particularly sealing bellows for joints, for example ball joints in automotive vehicles, including followers which are divided centrally in the longitudinal direction of the sealing element and form the outer contour. The mold has a core plunger which forms the inner contour and is divided into an upper core plunger part and a lower core plunger part which are movable relative to each other. The sealing element is removed from the foregoing parts after the opening of the followers. In order to be able to remove the sealing element automatically from the mold without the use of parting agent the followers are split in transverse direction into an upper and a lower pair of followers in the region between the inner undercut of smallest diameter and the outer undercut of smallest diameter. The pairs of followers are movable independently of each other for successive gripping of the sealing element during the opening of the mold.
U.S. Pat. No. 4,975,041, which issued to Fries et al on Dec. 4, 1990, discloses a die assembly for die casting a propeller structure. The die assembly is used for casting a propeller structure, such as a wax propeller pattern. The pattern, which is identical in configuration to a cast metal propeller to be produced, includes a generally cylindrical hub having an outwardly flared end and a plurality of blades which project outwardly from the hub. The die assembly includes a base plate and a lower core section extends upwardly from the base plate through an opening in a stripper plate, which is mounted for movement towards and away from the base plate. A plurality of die sections are mounted for generally radial sliding movement on the stripper plate from an outer open position to a closed position where they define a die cavity with the core section. The die assembly also includes an upper die unit that is mounted for vertical movement and has a cavity in its lower surface which receives the upper ends of the die sections when in the closed position. An upper core section is carried by the upper die unit and meets with the lower core section when the upper die unit is lowered into interlocking relation with the die sections. Liquid wax is introduced through an ingate to the die cavity to form the wax propeller pattern. A mechanism is provided to rotate the lower core section and the wax pattern after the die sections have been moved to the open position to move the blades of the pattern to facilitate axial removal of the pattern.
All of the above United States patents described above are hereby explicitly incorporated in this description of the present invention.
Die assembly apparatus for manufacturing wax propeller structure patterns which are known to those skilled in the art present two disadvantages. First, the die assembly is typically very heavy and expensive to manufacture. Secondly, known techniques for filling the die cavity with molten wax leave certain imperfections in the finished wax pattern because of the manner in which the molten wax is typically injected into the mold cavity.
It would therefore be significantly beneficial if a die assembly structure could be provided which is lighter in weight, less expensive to manufacture, and able to produce wax patterns that do not exhibit the imperfections that currently exist when known die assemblies are used.